It doesn't apply to them because they're doing it from Buffy's side, they're fighting from her side, they're in her team, they fight together in the same system, they're not another seperated operation that fights demons the wrong way.
And Buffy doesn't always encourage it if at all. When it's too dangerous she tells them that she'll do it alone. There wasn't ever a scene where she says to tell: "you wanna help? that's great! I would love it if you risk your life along with me!" Quite the contrary, she wants them to stay out if it's no place for them. She knows where the limit is, she knows when it's the time to be a Slayer only mission.
Buffy has become a better Slayer BECAUSE of her friends. They gave her a reason to fight. She might have needed their help from time to time, but she's not a bad Slayer. The fact that they helped her doesn't mean she's a bad Slayer, I don't see the connection. They just made her better. And yeah, they saved her life, even if not directly, and it's great that they're there, and they should be there, but not all the time, not when it's not their place (and Buffy knows that). But when they are there, it's because they're doing it right, because they take orders from the Slayer herself. The Initiative relied on information the goverment and scientist told them. It was probably not the right way to go, because it didn't work, and we saw it fail! And Forrest was stuck on the idea that they know best and the Slayer doesn't, even though it's a tradition of thousands of years.
Forrest's help? The one time they tried fighting along with each other he was killed! Needed him? Don't think so. He's a poor fighter, because he does it wrong. The whole Initiative are, because they don't know the demon world as well as they think. That's why the operation failed, that's why Riley drifted, that's why Forrest died.
The common thing between them is that they both fight evil. But the difference, and that's a big one, is that Buffy is doing it right, he doesn't. That's why he was killed by Adam in a really stupid way. Of not listening to the one person who knows what she's doing, because he didn't know best, even if he thought he did. That's the mistake. Buffy IS a better fighter than him, and he can't admit that. He's too full of himself that he doesn't run away from the cave when Buffy tells him to. And he dies in a very stupid way, because he is stupid, thinking he knows better than the Slayer. He doesn't! The two times Buffy died, it was a sacrifice. She lasted longer than any known Slayer because she was surrounded by people that both loved her (and gave her a hang of life), and faught at her side (not seperated from her in a wrong way that failed, because that gang didn't fail, they last till today). Bottom line of this: Forrest just thinks he's a hero. Buffy IS a hero.